Flash Flood in Arizona, July 11, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
126 PM MST FRI JUL 11 2014

.SYNOPSIS...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED TODAY THROUGH THIS WEEKEND...ESPECIALLY FROM TUCSON
EASTWARD. OTHERWISE...A CHANCE OF THUNDERSTORMS WILL CONTINUE INTO
NEXT WEEK. MOST STORMS WILL OCCUR DURING THE AFTERNOON AND EVENING
HOURS BUT SOME WILL LINGER OVERNIGHT. SOME STORMS WILL PRODUCE
LOCALLY HEAVY RAINFALL AND STRONG WINDS.

&&

.DISCUSSION...LATEST VISIBLE SATELLITE IMAGERY AND KEMX RADAR DATA
INDICATE SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS THE WHITE
MOUNTAINS INCLUDING GREENLEE COUNTY INTO THE GILA REGION OF NEW
MEXICO. MEANWHILE...THE REST OF THE FORECAST AREA IS STARTING TO SEE
SOME SHOWERS AND THUNDERSTORMS DEVELOP ON THE HIGHER TERRAIN. THE
CONVECTION IN GREENLEE COUNTY IS BEING AIDED BY A DISTURBANCE MOVING
INTO WESTERN NEW MEXICO. MEANWHILE...THERE IS A LARGE SCALE UPPER
LOW/INVERTED TROUGH NOW ACROSS EASTERN CHIHUAHUA. AS THESE FEATURES
CONTINUE TO MOVE WEST...THE STEERING FLOW WILL CONTINUE TO BECOME
MORE EASTERLY AS THE AFTERNOON PROGRESSES. THE BEST CHANCE FOR
STORMS THIS AFTERNOON AND INTO THIS EVENING ARE EXPECTED TO BE
MAINLY SOUTH AND EAST OF TUCSON WITH LESSER CHANCES TO THE NORTH AND
WEST OF TUCSON AS SOMEWHAT DRIER LOW LEVEL AIR ADVECTS IN FROM THE
WESTERN DESERTS FROM THE TUCSON AREA WESTWARD. THUS...AS PER THE 12Z
UOFA WRF-NAM AND GFS...EXPECT THE STORMS TO STRUGGLE SOMEWHAT AS
THEY MOVE INTO THE VALLEYS FROM TUCSON WESTWARD. ONE POTENTIAL
THREAT IS FOR SOME GUSTY OUTFLOWS MOVING NORTHWEST INTO THE DESERTS
TO PRODUCE LOCALIZED REDUCED VISIBILITY DUE TO BLOWING DUST. THIS IS
SOMETHING WE'LL BE KEEPING AN EYE ON AS WELL.

HEADING INTO THIS WEEKEND...WE WILL BE WATCHING THE INVERTED TROUGH
NOW IN EASTERN CHIHUAHUA CONTINUE TO PUSH WEST. EXPECT DEEP LAYER
EAST TO NORTHEAST FLOW SATURDAY WHICH IS NORMALLY FAVORABLE...BUT
PWAT VALUES ARE PROGGED TO BE DOWN TO ABOUT 1.2 INCHES AS THAT LOWER
LEVEL DRIER AIR MENTIONED ABOVE CONTINUES TO IMPACT MAINLY THE
WESTERN HALF OF THE FORECAST AREA. THUS...WHILE WE EXPECT SCATTERED
SHOWERS AND THUNDERSTORMS FROM TUCSON EASTWARD...THEY WILL HAVE SOME
TROUBLE PUSHING SOUTHWESTWARD INTO THE LOWER DESERTS DUE TO THE
DRIER AIR.

BY SUNDAY...MOISTURE VALUES ARE PROGGED TO BE ON THE INCREASE AGAIN
AS THE DAY PROGRESSES. THIS IN COMBINATION WITH STRONGER EAST TO
SOUTHEAST STEERING FLOW SHOULD RESULT IN BETTER COVERAGE OF SHOWERS
AND THUNDERSTORMS...WITH THE POTENTIAL OF GETTING ALL THE WAY INTO
THE WESTERN DESERTS AS WELL. THE FLASH FLOODING THREAT WILL LIKELY
BE REDUCED THIS WEEKEND AS WELL DUE TO QUICKER STORM MOTIONS WITH
PERHAPS AN INCREASED SEVERE STORM THREAT.

FOR NEXT WEEK...AN OVERALL ACTIVE PERIOD IS EXPECTED TO START THE
WEEK...PERHAPS TRENDING BACK TOWARDS A LOW TO MID GRADE MONSOON
PATTERN BY THE MIDDLE OF NEXT WEEK AS THE MID/UPPER LEVEL HIGH
CENTERS ITSELF MORE OVER ARIZONA.

&&

.AVIATION...ISOLATED TO SCATTERED TSRA OVER THE MOGOLLON RIM AND
WHITE MOUNTAINS OF EAST CENTRAL ARIZONA AND INTO WEST CENTRAL NEW
MEXICO WILL CONTINUE TO MOVE WEST THROUGH THE AFTERNOON INTO PARTS
OF GRAHAM COUNTY NEAR KSAD. SHRA/TSRA'S WILL DEVELOP OVER COCHISE
COUNTY AND SPREAD WEST DURING THE AFTERNOON AND INTO THE EVENING
HOURS OVER PARTS OF SOUTHEAST ARIZONA...POTENTIALLY AS FAR WEST AS
KTUS. A LESSER CHANCE OF STORMS W OF KTUS...BUT STILL ISOLATED TO
LOW END SCATTERED DEVELOPMENT. MVFR VSBY NEAR +TSRA...AS WELL AS
WIND GUSTS MOSTLY AROUND 35-40 KTS. OTHERWISE...CLOUD DECKS WILL BE
AROUND 8-15K FT AGL. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.

&&

.FIRE WEATHER...MOISTURE WILL REMAIN SUFFICIENT TO PROVIDE SCATTERED
TO PERHAPS NUMEROUS MAINLY AFTERNOON AND EVENING THUNDERSTORMS INTO
NEXT WEEK.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

&&

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GL